Data storage apparatus and controlling method of the data storage apparatus

Abstract

According to one embodiment, a data storage apparatus includes a first nonvolatile storage, a second nonvolatile storage and a controller. The controller is configured to control data writing and data reading for the first and second nonvolatile storage. The controller includes an allocation control module. The allocation control module is configured to allocate part of a storage area of the first nonvolatile storage to a logical address space and to allocate part or all of a storage area of the second nonvolatile storage to the logical address space in order to use the part of the storage area of the first nonvolatile storage allocated to the logical address space as storage area of substantial data, and to use part or whole of a remaining part of the storage area of the first nonvolatile storage not allocated to the logical address space as nonvolatile cache for the second nonvolatile storage.

1 . A data storage apparatus comprising:
 a first nonvolatile storage;   a second nonvolatile storage; and   a controller configured to control data writing and data reading for the first nonvolatile storage and the second nonvolatile storage,   wherein the controller comprises an allocation control module configured to control allocation of storage areas of the first nonvolatile storage and the second nonvolatile storage to a logical address space, the allocation control module being configured to allocate part of a storage area of the first nonvolatile storage to a logical address space and to allocate part or all of a storage area of the second nonvolatile storage to the logical address space in order to use the part of the storage area of the first nonvolatile storage allocated to the logical address space as storage area of substantial data, and to use at least some of a remaining part of the storage area of the first nonvolatile storage that is not allocated to the logical address space as nonvolatile cache for the second nonvolatile storage.   
     
     
         2 . The apparatus of  claim 1 , wherein:
 the first nonvolatile storage comprises a nonvolatile semiconductor memory; and   the second nonvolatile storage comprises a magnetic disk.   
     
     
         3 . The apparatus of  claim 2 , wherein the controller further comprises a wear leveling control module configured to level the numbers of erases for the whole storage area of the nonvolatile semiconductor memory. 
     
     
         4 . The apparatus of  claim 1 , wherein the allocation control module is configured to allocate the part of the storage area of the first nonvolatile storage to a part starting from a head address of the logical address space, and to allocate all the storage area of the second nonvolatile storage to a part of the logical address space starting from an address following the part of the logical address space to which the part of the storage area of the first nonvolatile storage is allocated. 
     
     
         5 . The apparatus of  claim 1 , wherein the allocation control module is configured to allocate the part of the storage area of the first nonvolatile storage to a part from a head address to a predetermined address of the logical address space. 
     
     
         6 . The apparatus of  claim 1 , wherein the allocation control module comprises a setting module configured to set a capacity of the part of the storage area of the first nonvolatile storage to be allocated to the logical address space, based on a command input. 
     
     
         7 . The apparatus of  claim 1 , wherein the allocation control module is configured to allocate the part of the remaining part of the storage area of the first nonvolatile storage, which is not allocated to the logical address space, as nonvolatile cache region for the second nonvolatile storage, and to allocate a remaining part of the remaining part of the storage area of the first nonvolatile storage as management data storage area to store management data. 
     
     
         8 . The apparatus of  claim 7 , wherein the allocation control module comprises a setting module configured to set a capacity to be allocated as the nonvolatile cache area for the second nonvolatile storage and a capacity to be allocated as the management data storage area to store the management data, among the remaining part of the storage area of the first nonvolatile storage, based on a command input. 
     
     
         9 . A control method of a data storage apparatus comprising a first nonvolatile storage and a second nonvolatile storage, the method comprising:
 controlling allocation of storage areas of the first nonvolatile storage and the second nonvolatile storage to the logical address space,   wherein the controlling comprising allocating part of a storage area of the first nonvolatile storage to a logical address space, and allocating part or all of a storage area of the second nonvolatile storage to the logical address space in order to use the part of the storage area of the first nonvolatile storage allocated to the logical address space as storage area of substantial data, and to use at least some of a remaining part of the storage area of the first nonvolatile storage not allocated to the logical address space as nonvolatile cache for the second nonvolatile storage.   
     
     
         10 . The method of  claim 9 , further comprising leveling the numbers of erases for the whole storage area of a nonvolatile semiconductor memory, which is included in the first nonvolatile storage as the storage area.